Unable to configure Broadcaster cache with web.xml when using AtmosphereHandlerService Annotation

[Darrelk]

I am trying to add the UUIDBroadcasterCache to my application. In the documentation (https://github.com/Atmosphere/atmosphere/wiki/Understanding-BroadcasterCache) it says that I just need to add the following to the web.xml:

 <init-param>
   <param-name>org.atmosphere.cpr.broadcasterCacheClass</param-name>
   <param-value>org.atmosphere.cache.UUIDBroadcasterCache</param-value>
 </init-param>

So I added the above to my web.xml, but still the following message gets printed when I start the application:

 WARN  o.atmosphere.cpr.AtmosphereFramework - No BroadcasterCache configured. Broadcasted message between client reconnection will be LOST. It is recommended to configure the org.atmosphere.cache.UUIDBroadcasterCache

I did some debugging and discovered the following:

• The framework first sets the Cache class from the web.xml , but does not use that.
• It then goes trough the Handler annotations (AtmosphereHandlerServiceProcessor), then overrides the cache class with what ever is in there, so if there is nothing, it uses the "org.atmosphere.cache.DefaultBroadcasterCache"

[jfarcand]

@Darrelk The idea here is to add aboolean in AtmosphereFramework and use that flag in the xxxProcessor to discard the annoation's value. Just in case you want to contribute :-)

[elakito]

@jfarcand While relabeling my own 2.3.0 issue to 2.3.1, I saw this 2.3.0 issue. I haven't looked at the code, so I don't know how it looks inside, but I'm wondering whether the code can be simply changed to not override the cache that is already explicitly set via web.xml. In that way, we wouldn't need an extra boolean flag.

[jfarcand]

@elakito I didn't wanted to touch that code for 2.3.0 as it can have side effets...but yes it should be simple and should be done in 2.3.1.

[Darrelk]

@jfarcand So to fix this issue, Which of the following solutions do you prefer?

1. Add a new config setting like "org.atmosphere.cache.forceConfig":
   • When this config is true, it will use the setting from the web.xml file
   • When this setting is false or not specified, it will use the class specified in the annotation.
2. Only use setting in web.xml if no annotation specified:
   • If "org.atmosphere.cpr.broadcasterCacheClass" is specified in the web.xml and no annotation class specified, then use the web.xml class.
   • If no web.xml class specified and no annotated class, use default.

I will implement and do a pull request when done.

[jfarcand]

@Darrelk (2) is the best IMO. Thanks!